Conventional footwear (e.g., shoes and sneakers) comprises a sole and an upper secured to the sole on a lower portion of the upper. The top of the upper includes an opening, typically near the back part of the upper, where the foot enters the cavity formed by the upper and the sole. The entire structure functions to support the foot. The sole is the portion between the foot and the ground. The sole is intended to provide traction, support and cushioning for the user. Many soles have a multi-part construction including an outsole, a midsole, and an insole. The insole is located on the upper most portion of the sole, typically with an upper surface exposed inside the footwear where the user's foot contacts the sole. The outsole is located on the bottom most portion of the sole of the footwear. The underside of the outsole contacts the surface on which the user walks or runs (the bottom of the sole contacts the ground and provides traction against the surface on which the user walks) and is designed for durability and traction. The midsole is located between the insole and the outsole and it is commonly designed to absorb the forces commonly encountered when walking or running in the footwear. One or more parts of the sole, including each the insole, midsole, and outsole, may include padding/cushioning and/or be made of materials that create cushioning for comfort and for shock absorption properties.
For most footwear the sole also includes a passive medial arch support. The passive medial arch support is a raised part/portion of the sole positioned in the location where the medial arch of the user's foot rests on the insole. In most footwear, the passive medial arch support is located on the medial side (inside) of the footwear in a lateral direction and about midway between the front and the back of the footwear in a longitudinal direction. Passive medial arch supports are typically convex in at least two directions to complement and conform to the shape of the user's medial foot arch. To achieve the shape of the passive medial arch support, the sole of the footwear can be shaped to form the passive medial arch support and/or the footwear can include padding/cushioning as part of the sole (typically the insole) to create the passive medial arch support. The flexibility of the passive arch support cushion and its ability to compress when the foot's medial arch contacts the passive arch support cushion allows, to some extent, for use by people with different arch heights, widths and shapes, although not every user's medial arch is comfortably supported by the standard passive arch supports inside footwear. Accordingly, it is not uncommon for users to add to the passive medial arch support inside footwear with inserts or to modify the passive arch support and/or the insole shape using orthotics for improved comfort.
With the foot inside the footwear, the foot rests on top of the insole and contacts at least some parts of the inside of the upper. For footwear having a passive medial arch support, the medial arch of the user's foot rests upon the passive medial arch support causing upward forces on the user's medial arch when weight is applied onto the footwear.
There are many different types of soles. Some footwear uses a very rigid sole intended to provide resistance to penetration, such as, for example, steel plated construction boots/shoes. Some footwear includes a less rigid sole which provides rigidity but with also provides some flexibility, such as, for example, in athletic footwear with spikes (e.g., soccer shoes, baseball spikes/cleats, football cleats, etc.). Still further there is footwear with a strong and durable sole which provides some flexibility but also provides a different appearance more appealing for formal use, the sole intended to last for an extended period of time, such as, for example, dress shoes. Footwear also exists with a light and flexible sole intended to provide comfort and improve balance, typically when exercising but also during daily use (walking), such as, for example, sneakers and running sneakers. Sneaker soles are typically made for motion during use and include padding to absorb impact forces associated with foot strike.
Some footwear has a split sole design with a front sole portion/section and a back sole portion/section, without a middle sole portion/section. In split sole footwear, the front sole portion/section and the back sole portion/section are connected to each other using the upper. Split sole footwear also often includes a heel pad and a toe pad made from a rough material, such as leather or suede, to offer traction. The middle section of the split sole footwear (sometimes both over and under the foot) is covered and protected only by the material used for the upper. Split sole footwear usually provides less arch support to the user (along the user's medial arch as well as the lateral arch) than full sole footwear and thus those arches of the foot may be vulnerable to injury during use. An advantage of split sole footwear is that it may provide more traction in certain environments, such as, for example, for rock climbing where the split sole allows for greater flexibility of the footwear which assists with contact with uneven or rocky terrain. As another example, hunters may use split sole footwear for quieter movement than full sole footwear. In addition, split sole shoes are considered aesthetically pleasing, especially in the dance industry, because they make the line of the foot appear more flattering. A split sole shoe is particularly useful for dancers who need to bend their foot and/or point their toes, such as, for example, in ballet. Such footwear, however, does not provide support for the foot, particularly in the midsection where there is no sole.
Still further, there is footwear designed to improve/assist the user with walking/running through the use of mechanical devices located in the footwear. For example, some footwear includes one or more springs within the sole, typically located in the heel region, to create lift during a push off phase (of the Gait Cycle) or when jumping. Other footwear includes encapsulated air pockets within the sole, also typically in the back portion of the sole to create increased cushioning. Mechanical devices such as springs or air pockets in the sole provide shock absorption properties that relieve some of the stress and fatigue of walking or running.
Some recent footwear marketed for running includes channels or grooves in the outsole to increase outsole flexibility between the forefoot section and the heel section of the sole, such as, for example in the Nike® Free 3.0 Flyknit. The segmented sole may benefit the user by strengthening the muscles in the foot. The outsole is made of lightweight material to try to give the feeling of running barefoot while still giving a cushioned support to the user's foot. Some segmented outsoles are also configured with a ratio of the heel-to-toe height smaller than in a traditional sneaker or running shoe to encourage forefoot strike as opposed to a heel strike when running.
Many runners, especially those who wear traditional running shoes, strike the ground heel first while running. Due to this reason, traditional running shoes usually have added height and cushion in the midsole and outsole of the heel portion of the shoe, causing a larger heel-to-toe height ratio. The added cushioning seeks to provide comfort to runners by reducing the impact of the heel strike phase on the foot and skeletal system. In heel striking, as understood in the context of the gait cycle (the conventional six phases/steps of the gait cycle are 1) heel strike, 2) foot flat, 3) mid-stance, 4) heel-off, 5) toe-off, and 6) swing) the collision of the heel on the ground generates a significant impact force on the skeletal system, whereas in forefoot striking, the collision of the forefoot with the ground causes less effect on the skeletal system.
Applicant has discovered that the existing footwear impedes the natural shock absorptive and cushioning capabilities of the human foot. Existing footwear with passive arch support(s) limits the foot's natural ability to achieve superior arch compression of the foot structure (including bones, muscles and ligaments) which provides shock absorption and cushioning for the user's foot and body. Similarly, the structure of existing footwear with passive arch support(s) limits the energy absorbing and dissipation characteristics of the foot. In addition, most existing footwear causes splaying of the foot along at least one of the medial arch, the lateral arch and the transverse arch, which causes discomfort for some including the feeling of a tight shoe or sneaker.
Throughout the gait cycle, the arches of the foot experience fluctuation of compressive forces due to the different placement of body weight forces at each stage and the reaction of the foot's biomechanics. Spacing and the shapes of the bones in the human foot enable the human foot to achieve two different types of compression of the bones depending on the position of the foot and the direction of the forces.
As used herein, the phrase “inferior compression” refers to the state of the human foot when compressive forces are applied along inside arch(es) of the foot causing the parts of the bones of the foot along the inside of the arch(es) to touch together. FIG. 12 shows a side view of the human foot depicting inferior compression along the medial arch with the bones touching along the inside of the arch and separated along the outside of the arch. Inferior compression of the medial foot arch typically occurs during the heel-off phase of the gait cycle when the foot is plantar flexed and the big toe is dorsiflexed causing a longitudinal stretching of the plantar fascia tissue shortening the distance between the calcaneus and metatarsals (arch base decreases) to elevate the medial longitudinal arch (arch height increases), as seen in FIGS. 13, 12, 2 and 2A. The plantar shortening that results from plantarflexion of the foot and dorsiflexion of the big toe is the essence of the “Windlass Mechanism” of the foot that helps with propulsion by creating a stable arch and hence a more rigid level for push off. Notably, with footwear having a passive medial arch support, the footwear limits the ability of the longitudinal arch base to shorten preventing inferior compression and thus decreasing the effect from the windlass mechanism of the foot. In some cases for footwear, when in a heel-off stage, the passive medial arch support in the footwear pushes against the plantar fascia forcing it in another direction (e.g., upwards towards the top of the user's foot) which can cause pain and discomfort.
As used herein, the phrase “superior compression” refers to the state of the human foot when compressive forces are applied along the outside arch(es) of the foot causing the parts of the bones of the foot along the outside of the arch(es) to touch together. FIGS. 13, 11, and 2 show a side view of the human foot in the flat foot phase depicting superior compression along the medial longitudinal arch with the bones touching along the outside of the arch and separated along the inside of the arch. Splaying occurs in an arch, such as, for example in the foot arch(es), when weight is applied on the outside of the arch causing the arch height to decrease and causing the arch base to increase (widen) as shown in FIG. 2 where y2<y<y1 and x2>x>x1. For the transverse arch of the foot, the forefoot flattens and the arch height decreases, causing widening of the forefoot as well as potential damage or irritation to the nerve under the ball of the foot. Splaying can also be caused by applying too much pressure to the foot, for example by wearing high heels or by being overweight. Injury or disease, such as diabetes, may also cause splaying by compromising bone and soft tissue integrity. Morton's neuroma is a painful condition that is often associated with splayfoot as it may be caused by irritation or damage to the intermetatarsal plantar nerve.
A passive medial arch support such as the arch pads commonly found inside footwear, provides a filler of arch concavity. It supports the medial longitudinal arch of the user during weight bearing (at the flat foot stage of the gait cycle) when walking and/or running keeping the foot arch structure in a middle position (between a state of inferior compression and a state of superior compression) and thus not rigid. The uncompressed position hinders normal foot biomechanics of arches splaying. Since ground forces dissipate through the passive arch support, force fluctuation is restricted, there are no arch compressive forces either inferior or superior and thus the natural arch neutralizing and shock absorption properties of the foot are diminished. Passive arch supports also have a long term deleterious effect on the foot; they passively hold the foot as if in a cast sometimes causing osteoporosis, muscle and ligaments atrophy, with a loss of ligament integrity which maintains the architectural structure of the foot. Consequently, when walking barefoot without a passive arch support after experiencing these deleterious effects, the foot effectively “Hyper-Splays” due to the loss of ligament integrity without achieving arch rigidity (Flat Foot) and is weak and unstable.
None of the existing footwear is capable of providing a user with a dynamic arch support system that increases the users' medial arch rigidity when the user pushes down on the insole (e.g., during the flat foot and mid-stance stages of the gait cycle), an arch support system that increases footwear comfort and also provides assistance with walking and/or running through propulsion. None of the existing footwear lessens the splaying of the user's foot along the medial longitudinal arch and/or the transverse arch for increased comfort. None of the existing footwear increases the rigidity of the arch support(s) when loading to help achieve an inferior compression of the user's foot (as opposed to superior arch compression which occurs during arch splaying) creating improved shock absorption and cushioning effects. None of the exiting footwear provides a convex shaped outsole with opposing wedge shaped configurations in the bottom of the forefoot sole section and the heel sole section which provide rotation of the forefoot sole section and the heel sole section in opposite directions when weight is applied.
None of the exiting footwear provides a convex shaped, split sole (in the longitudinal direction) with an outsole having opposing wedge shaped configurations in the bottom of the forefoot sole section and the heel sole section that provide rotation of the forefoot sole section and the heel sole section in opposite directions when weight is applied.
None of the exiting footwear provides a convex shaped outsole transversely across the width of the footwear in the forefoot section with opposing wedge shaped configurations which provide rotation of the medial side and the lateral side of the forefoot sole section in opposite directions when weight is applied.
None of the exiting footwear provides a convex shaped outsole transversely across the width of the footwear with a split sole and with opposing wedge shaped configurations in the forefoot sole section which provide rotation of the medial side and the lateral side of the forefoot sole section in opposite directions when weight is applied.
None of the exiting footwear provides a flexible, elastic, member between the forefoot sole section and the heel sole section configured to increase cushioning effects, store and dissipate energy thereby assisting with propulsion, and which increases foot comfort by reducing splaying. None of the existing footwear provides a split sole with a flexible, elastic, member between the forefoot sole section and the heel sole section configured to increase cushioning effects, store and dissipate energy thereby assisting with propulsion, and which increases foot comfort by reducing splaying.
None of the existing footwear provides a flexible, elastic, member transversely positioned in the forefoot sole to increase cushioning effects and comfort by reducing splaying. None of the exiting footwear provides a split sole with a flexible, elastic, members longitudinally and transversely in the forefoot sole section to increase cushioning effects and comfort by reducing splaying.
No existing footwear provides a dynamic arch support comprising an elastic member connected at opposing ends to rotatable wedges which, when force is applied on the wedges, causes the wedges to rotate and in some cases slide thereby bending the elastic member, increasing the energy stored in the elastic member, and creating arch support.
No existing footwear includes at least one pair of rotatable wedges positioned in a location in the footwear such that they are along at least one of the medial arch, the lateral arch, and the transverse arch of the user's foot when worn, wherein the wedges rotate and slide thereby reducing splaying and pronation of the user's foot.
None of existing footwear provides a mechanism to help the user's foot achieve inferior compression of the medial arch during the flat foot phase which relaxes the plantar fascia tissue due to a decrease in distance between the calcaneus and metatarsals.
Existing footwear also attempts to cushion the impact forces on the body during walking or running. The impact of the heel during walking or running (the heel strike (HS) phase of the walking Gait cycle) generates a ground reaction force on the foot and thus the body of the user which is proportional to the force of impact. There are also forces on the user's foot and body during other phases of the Gait cycle, e.g., at the stance phase where the foots arches and the forefoot have ground forces on them. Existing footwear uses cushioning systems and methods to reduce the resulting forces on the user's body such as, for example, padded insoles, elastic and compressible midsoles and/or outsoles (e.g., rubber compounds), and/or soles with air pockets of springs or the like. The shock absorption properties of most footwear is achieved by variation in the material composition and/or thickness of the footwear at the heel, the arch support, and/or the forefoot. Materials such as rubber, plastic, air or liquids are used in various degrees and combinations. Ideally, the footwear seeks to achieve shock absorption without compromising foot and heel stability while also providing comfort style and enhance athletic performance when desired. Unfortunately, existing technologies achieve some goals while compromising others—increased stability with less shock absorption or increased shock absorption with less stability or more comfort and less a style or more style and less comfort.
An effective cushioning method or system needs to supplement the inherent force dissipating properties of the foot's bones and soft tissue and biomechanics. The higher shock absorption capacity of the footwear (and the user's heel, arch and forefoot) the less ground force transmission transmitted to toward the user's body and therefore, the less likelihood of injury and/or aggravation of pathology state of the foot, leg or spine.
There is a need for footwear with a shock absorbent, spring-like effect. There is a need for improved footwear capable of storing and releasing energy generated by gravity (weight). There is a need for footwear that can store energy generated by gravitational forces and can release the energy in the form of kinetic energy at the desired stage of walking or running (of the Gait Cycle) thereby assisting forward propulsion.
None of the exiting footwear provides 1) a convex shaped, split sole (in the longitudinal direction) with an outsole having opposing wedge shaped configurations in the bottom of the forefoot sole section and the heel sole section that provide rotation of the forefoot sole section and the heel sole section in opposite directions when weight is applied, and 2) a concave shaped outsole transversely across the width of the footwear at the forefoot sole section and/or the heel sole section.
None of the existing footwear provides an outsole having a plurality of wedge shaped segments in each of the forefoot sole section and the heel sole section, where each segment in the each of the forefoot sole section and the heel sole section are sloped downward (away from the upper) from an innermost portion of the segment located at an indentation central to the segments, wherein each segment slopes downward (away from the upper) to an outermost portion of the segment, thereby providing downward movement of the indentations in forefoot sole section and the heel sole section when weight is applied.